Portable oxygen aviation unit



July 13, 1943. J.A. HEIDBRINK PORTABLE OXYGEN AVIATION UNIT 5 heets-Sheet 1 Filed March 17', 1941 Inventof: B3215 K. HeLdbr-ink. WW /$3 July 1943- J. A. ,HEIDBRINK PORTABLE OXYGEN AViATION UNIT Filed March 17, 1941 5 Sheet s-Sheet 2 Inventor-z mxm July 13, 1943. J. A. HEI DBRINK PORTABLE OXYGEN AVIATION UNIT Filed March 17, 1941 5 Sheets- Sheet 3 2 F U4 9 3 8 6 o k 2 an m wz mu m +.n Z i r w l l 6 r O I 6 ..v m L a ag t O W- I@ A II 2 HM o m m a MK m w w 9 I 45... 35 l w us a 7.5 B 29 o 8 B3 .9 2 w 2 OJ 8 1 m ,F w O 2 M t V I u W o v 2 o w k u I Q m m L OJ mwfim mm m J. A. HEIDBRINK PORTABLE OXYGEN AVIATION UNIT 5 Sheets-Sheet 4 Filed March 17, 1941 July 13, 1943.

July 13, 1943'. J, A, HEIIDBRINK 2,324,389

PORTABLE OXYGEN AVIATION UNIT Filed March 17, 1941 5 Sheets-Sheet 5 IIHIHII Patented July 13, 1943 PORTABLE OXYGEN AVIATION UNIT Jay A. Heidbrink, Minneapolis, Minn., assignor to Air Reduction Company, Incorporated, New York, N. Y., a corporation of New York Application March 17, 1941, Serial No. 383,713

6 Claims.

My invention relates to a portable oxygen aviation unit and has for its object to provide in a readily transportable framework or casing a supply of oxygen connected through control means with a suitable mask to be worn by an aviator, passenger or any person in an air transport device which moves to such elevations that added oxygen for respiration is required.

Means for furnishing oxygen to aviators at great altitudes in practice has been provided mounted in and connected with the airplane structure and employing tanks holding relatively large quantities of compressed oxygen, which tanks are necessarily of considerable weight. Such means for supplying oxygen to the pilot or occupants of an airplane at high altitudes necessarily go with the plane, and airplanes which are not so equipped may be for that reason prohibited from going up into high altitudes where it might be desirable to fly the plane. On the other hand such planes may in general not be intended to go to high altitudes. Hence, with my portable unit available at hangars and flying fields, it will be 1 practicable, for flights into high altitudes, to equip airplanes otherwise unequipped with quickly available means to supply a suitable amount of oxygen for such high altitude flights.

It is a principal object of my invention, therefore, to provide a small and relatively light assemblage having therein a tank or container of oxygen with passages connected therewith and control means in said passages, said passages finally connected to a suitable oxygen mask, the entire assemblage being readily transportable, so that one or more of said units may be readily taken into and from any airplane as desired and thereby furnish the pilot and other occupants with sufiicient added oxygen at altitudes too high for safe normal breathing of such high altitude atmosphere.

It is a further object of my invention to provide such control means as will regulate the delivery of oxygen in a predetermined volume to the breather with automatic adjustment of said regulation for decreased atmospheric pressure due to elevation and for temperature changes.

The full objects and advantages of my invention will appear in connection with the detailed description thereof, and the particular features of invention by which the desired advantages are obtained are particularly pointed out inthe claims,

In the drawings: Fig. 1 is a top plan view of my oxygen delivering portable unit with some parts broken away.

Fig. 2 is a sectional elevation view taken on line 2-2 of Fig. 1.

Fig. 3 is a sectional partial plan view taken on line 33 of Fig. 2.

Fig. 4 is a sectional plan view of a part of what is shown in Fig. 3 taken on line 4-4 of Fig. 12.

Fig. 5 is a sectional transverse elevation view taken on line 5-5 of Fig. 1.

Fig. 6 is a sectional elevation transverse view taken on line 66 of Fig. 1.

Fig. '7 is an end elevation view of a part of the unit taken on line '|1 of Fig. 10.

Fig. 8 is a sectional plan view of apart of the unit taken on line 88 of Fig. 10.

Fig. 9 is a part sectional plan view taken through the regulator valve at the top of Figs. 1 and 2.

Fig. 10 is a longitudinal sectional elevation view taken on line Ill-+1 I] of Fig. 1.

Fig. 11 is a sectional view taken on line I l--ll of Fig. l. I

Fig. 12 is a side elevation view showing the mounting of the flow gauge to permit it to swing into an erected position.

Fig. 13 is a sectional plan view similar to part of what is shown in Fig. 8 embodying a second gas outlet.

' Fig. '14 is a side elevation view of a modified frame for carrying the oxygen tank and parts connected therewith.

Fig. 15 is an end elevation view of the arrangement shown in Fig. 14.

Fig. 16 is a fragmentary sectional view taken on line l6|6 of Fig. 3.

Fig. 1'7 is an enlarged sectional view through a part of the regulator appearing at the bottom left of Fig. 1 showing the limit port for conducting gases from said regulator into the control system.

As illustrated, an open topped box, Figs. 1, 2, 5 and 6, is provided with a bottom 20, side walls 2| and 22, and end walls 23 and 24, it being noted that side walls 2| and 22 are the same height above bottom 20 as rear end wall 23, but slope downwardly as indicated at 25 to the front end wall 24 which is of considerably less height than An oxygen tank 28 is normally held upon sup-*- porting projections I9 extending upwardly from bottom 20 and against side wall 2| by means of a bar 29, Figs. 1 and 6, which is secured upon a threaded post-35 by means of a nut 3| bearing against a compression spring 32 and at its other end upon a post 33 having thereon a knurled hand nut 34. As shown in Fig. 1, the inner end 01 bar 29 is formed with a slot 35. Hence, in order to change tanks it is only necessary to screw up the knurled nut 34 sufliciently to take all pressure off of bar 29 when it can be swung to one side to permit the removal of one tank and insertion of a new tank. The manner'in which nut 3I is held upon spring 32 permits this swingin v movement.

The oxygen tank 28 is provided with a neck 35 having a passageway 31 leading from the interior- .of tank 28 and controlled bya valve in said pas sageway through operation of a valve handle 38 in a customary way. A fork 39, Figs. 1 and 5, has

- its prongs straddling the neck 36 and is provided with a portion 45 at right angles thereto which is secured by soldering, welding or the like to a shoulder 4|, Fig. 5, on a casting 42 surrounding a threaded bolt 43 screwed into an aperture 44 in the casting 42, which forms part of a regulating valve, Figs. 1 and 5, designated generally as per u e or chamber 44 has connected therewith a port or passageway 45 which leads into a valve chamber 41, Fi 9. As shown in Fig. 5, a port or passageway 45 leads from the chamber 41 to a transverse passageway 49. One part,

55, 01' passageway 49 leads to the primary pres-- sure gauge I. A second branch 52 from passageway 49 leads to a needle valv 53 which has its shank 54 passing through the stufling box 55 and is controlled by thumb screw 55 on the shank 54 for a purpose later to be given.

Referring to Fig. 9, within the valve chamber 41 is a valve head 51 urged toward a valve seat 58 by a compression spring 59 surrounding the valve stem 55. A guide pin extension 5| projects from the valve disc 51 and engages with its iree end a diaphragm forming and sealing the top of a chamber 53. Passages 54 lead from valve chamber 41 into diaphragm chamber 52. A powerful compression spring 55 in a housing 55 engages a plunger EIwhich in turn engages the diaphragm 52 and tends to force it against the end 01' pin 5| so as to push valve disc 51 away from the valve seat- 55. By means of a knurled nut 55 the degree of pressure which the spring 55 exerts upon the diaphragm 52 may b varied as desired whereby the pressure at which the gas is delivered, as indicated by the gauge, may be regulated.

For normal operation the gas passes from diaphragm chamber. through a port opening I5 to a passageway II. From passageway II the gas passes to a chamber in a head I2 to which is secured by a union I3, Fig. 5, pipe connections I4 and I5 with a flexible tubing connection I5 which runs, as indicated partly in dotted lines in Fig. 1, to a similar union connection 11 through a port I5 to a valve chamber I9 in a regulator valve block 55, from whence it passes through a union paessageway indicated at 5|, Figs. 1 and 3. From passageway H the gas goes to a chamber 52 in a block 53, Fig. 3, and thence through a port 54 and a pipe 55, Figs. 1 and 8, to a block 55 from which leads a port passageway 51, Figs. 8 and I5, entering a valve chamber 55 having a valve control hereinafter to be described.

As shown in Figs. 3 and 17 the port. I5 leading from passageway 11 is a limit port which conveys the gas into the valve chamber I5 in block 55. Regulation of volume or flow or gas from valve handle I so that more or less gas will pass in a customary manner to the union pas-- sageway 8|. This arrangement is employed in practice where it is found desirableto pass more or less gas through the flow valve by increasing or decreasing its delivery pressure.

The valve chamber 55 is located in an elongated block 59. From valve chamber 88, Fig. 8,

the gas is adapted topass through avalve passageway which is controlled by thermostat andaneroid means later to be describemom the passageway 95 the gas passes into a chamber 9| and thence through a port 92 intoa connector block 93, Fig. 8, thence by means of a flexible tube 94, Figs. 1 and 8, to a passageway within a second connector block 99, continuous with a passageway indicated in dotted lines at I55, Figs. 1 and 16.

Passageway I55 is continuous with a passageway through a tube I5I which extends through a stufiing box I52 into a casting I53, Fig. 16. The gas then passes through a bore I 54 in casting I53 to a'passageway I55 which extends into a passageway I55, Fig. 3, having diverging walls.

In passageway I55 is a piston I51 and stem I55 of a flow gauge, the stem I55 extending into a central passageway I59 ofa glass tube I I5 which is adjacent a gauge plate III, Fig. 1. As clearly shown, this plate has on one side altitude designations. the figures indicating thousands of feet, and flow designations which indicate liters oi oxygen delivered per minute. Passageway I55 is formed in a. tubular member II2 which is united with a casting block II3 that carries the tube H5 and the gauge plate III. Block II3 has an extension II4 carrying a-nipple, shown in dotted lines at H5 in Fig. 2. An opening II5, Fig. 3, leads through said block and nipple so as to discharge into a flexible tube connection I" which is' secured, as indicated in Figs. 2 and 12,

to the nipple II 5.

an oronasal mask structure I24 adapted to be secured by straps I25 and I25 upon awearer, the tube I 2I being-of suitable length to permit such securing. It will be noted that the escape opening I I5 from passageway I55 is at the end of said passageway remote from the gas inlet end, which,

traveling against the piston I51, forces it and v I the indicator rod I55 along the passageway I55 until the opening about piston I5I is suflicient to deliver the indicated amount of oxygen: and the endof the rod I55 in glass tube I I5, adjacent the columns of figures at either-sidethereoi' on the gauge plate II Lindicates the volume 01' 0!!- gen being delivered at different altitudes so that. the pilot or operator will at all times be informed as to whether a sufficient delivery of oxygen is in fact taking place.

It may be desirable to separatethe tube I2I' from the assemblage on the support and to facilitate this I provide a narrowed finger piece I2I, Figs. 2 and 11, which is held for ready removal by a bayonet slot I25 in which is received a pin I25 fast on the member I22, and a spring I55 surrounding an extension I3I from the block member H9 holds the parts in assembled position.

The support formed by the bottom and side walls 2I, 22, 23 and 24 is provided with feet I33, preferably of rubber, upon which the entire unit assembly may rest on a table, shelf, or the floor of an airplane, in any position convenient for observation. As the unit is carried the flow gauge structure, consisting of the parts III, H2 and H3 is depressed into a semi-horizontal position, as shown clearly in Fig. 2. This also is the position of this flow gauge device as it appears in Figs. 1 and 3. It isfrequently desirable, however, to

have this flow gauge in an erected position and the mounting for permitting that is shown in detail in Figs. 1, 3, 4 and 12.

Four plates I34, I35, I36 and I31, each formed with a central circular opening I19 secured in position by means of screws I38 a set of rubber discs I overlying similar openings on the bottom member 20 to which. the plates are screwed.

tands comprising bolts I40, I4I, I42 and I43 are secured upon the rubber discs and in turn support bottom plates I44 and I45 of a bracket member, U-shaped in cross section, having vertical limbs I46 and I41 and a horizontal table portion I48 supported thereby. Parts carried by the table I48 are thus cushioned against vibration or shock.

Bolted to the top plate I48, as indicated in Fig. 4, by means of bolts I50 and I5I is the base I52, Figs. 4 and 12, of a supporting standard I53 through which extends the passageway I00 and to which is integrally united the block 83, Figs.

1 and 3. Secured to the lower end of tube I I2 by means of a nut I54 is an extension member I55 through which passes the wire I05, Figs. 3 and 16, and which has in it the bore I04 leading to the gas passageway I00. The extension I55 has the laterally extended tubular portion 103 journaled inside of the supporting member I53, as clearly shown in Fig. 16.

The extension member I55 has formed thereon a centrally positioned boss I56 with a central threaded opening I51. A screw bolt i58 threaded into said opening secures to the boss in rigid position a triangular stop-piece I59 and a projecting arm I 80, these parts being held rigidly in adjusted position by means of a screw bolt I58. A

triangular stop I6I is adapted to have its faces I62 and I63 engaged by opposite end portions of the face I64 of the triangular stop-piece I59. A spring I65 is connected at I66 to a point near the end of a plate I61 fast on the bottom plate I45 of the bracket member. This spring is secured at its other end at I68 to the outer end of arm I60 and is so positioned that it swings past center to go from one position to another, as shown in Figs. 2 and 12 respectively, thereby holding with a toggle action the flow gauge in either its depressed or erected position as may be desired.

The block 89, as shown in Fig. 10, is secured to a supporting standard I69 by means of a bolt I18 which extends through the side wall ill of the block 89 and through the supporting standard I69 as indicated in dotted lines in Fig. 10. The bolt I10 is threaded at I12 into a bracket plate I13 which is supported on posts I14, Fig. 10, see cured by bolts I15 extending through the bracket plate I13 and posts I14, and the bottom plate 20, as clearly shown in Figs. 1 and 10. The posts I14 rest upon the bottom plate 20 and thus support the bracket plate I13. Bracket plate I13 has an upstanding bracket portion I16 of the form shown in Fig. '1. A bimetallic U-shaped thermostatic member I has one of its arms I8I secured by means of screw clamp plates I82 and I83 to the wing portions of bracket plate I16, as shown in Figs. 1 and 7.

The U-shaped thermostatic member I80 has its second arm I84 bifurcated at I85. The threaded end I 86 of a rod I81 is provided with two nuts I88 and I89 which clamp between them a block I90 having thereon diametrically opposed outwardly extending trunnion members I9I and I92 which have portions extending between clamping blocks I93 and I94 fastened by screws I95 to the respective portions I96 and I91 of the thermostat leg I84 which is thereby pivotally or swingably connected with the rod I86.

Rod I81 extends through a tubular member I98 and is pivotally connected by means of a pin I99 with a cylindrical member 200 which is sealed within the body of an aneroid 20I, as clearly shown in Figs. 8 and 10. The aneroid 20I is supported for sliding movements on the cylindrical extension I98 by a free fit of an opening in end wall 202 of the aneroid surrounding and engaging the cylindrical member I98, as indicated at 203 in Fig, 10. It follows that the position of the aneroid 20I is at all times dependent upon the relative positions of arms I8I and I84 of thermostat I80, that is, when, due to change in temperature, the arm moves to the left, as shown in Fig. 10, it will cause the entire body of the aneroid to partake of that movement. When it moves to the right the body of the aneroid will correspondingly move in the opposite direction.

The end plate 205 of aneroid 20! is provided with a cup extension 206, Fig. 10, which is adapted to receive the end of a plunger shaft 201. A washer cap 208 with a flange portion 209, together with a spring H 0, is adapted to hold a pin 2 extending through an opening in the end of rod 201 coupled to the cup portion 206.

The plunger rod 201 has a gas tight fit in an stat I80 and by the expansion of the thermostatitself due to changes of external pressure, such expansion thrusting against thermostat arm 184' and being translated to the front wall 205 of the aneroid.

Connected to the end of plunger shaft 201 and within chamber 9! of block 89 is a valve rod 213 which, as clearly shown in Figs. 9, 10 and 13, is cut away along one face, as indicated at 2I4. The diameter and circumference of the valve rod 2I3 are such that its end has a gas-tight fit in the-opening 90 connecting chambers 88 and 9| in'block 89. The cut-away portion 2I4 of valve rod 2I3 does not extend to the outer end of that rod but there is left a cylindrical portion 2I5 which will completely close the passageway between chambers 88 and 9I at normal elevations and temperatures, as clearly shown in Figs. 8, 10 and 13.

The operation of these instrumentalities will be apparent from the foregoing description. vAt normal elevations, such as those in which usually airplanes leave the ground, no oxygen will be passing to the mask because the flow of oxygen at its predetermined pressure is blocked by valve rod 2I5 in valve opening 90, and of course the mask will not then be worn. As higher elevations are reached and pressure falls the aneroid 20I expands and its front wall 205 operates to push the plunger 201 outwardly and with it the valve rod 2I3 and its cylindrical end 245. When this movement has progressed far enough to bring the end of the cut-away portion 2 beyond the opening 90 oxygen will begin to flow through opening 92 and tube 94 past flow gauge H2 and through pipes H1 and I2I to the rebreathing bag I23 and mask I24 where the wearer obtains the oxygen. As higher and higher elevations are reached the aneroid continues to expand with the result that the opening provided by cut-away portion 2| 4 continually grows greater, so that, without changing the pressure at which the oxygen is delivered to the system, the flow is automatically increased for difierent elevations, as shown by the flow gauge II2, by regular increase of the delivery port opening.

But as higher altitudes are reached, there will inevitably be increased cold which will cause the air or gas within the aneroid to tend to decrease in density volume thus offsetting to some degree the movement of the end 205 of aneroid 20I, so that uniform increase of port opening for uniform increase of elevation and pressure will not take place. However, as the cold decreases the density volume of air within the aneroid the bimetallic thermostatic member will move the aneroid and its endplate 205 bodily in the same .direction that the expansion of gas within the aneroid moves the end plate 205 with the result that the component of these two movements will always be the same as would bethe case it the temperature of the gas within the aneroid remained constant at its starting temperature. In this way temperature changes are compensated so that uniform and accurate increase or decrease of delivery of oxygenis efiected as changes in elevation and consequent changes in atmospheric pressure are encountered.

An important feature of my invention is re- H lated to the above defined and explained means for temperature compensated adjustment of'flow valve opening in the provision oi! an altimeter calibration plate III will inform of whether the delivery 01 oxygen at any indicated elevation is such as it should be. e

As shown in Fig. 13, instead of a single gas delivery chamber such as 89 in block 99 a wider block 229 may be employed having a second (or larger number) gas delivery chamber 229 and a gas inlet chamber 230 connected with gas inlet chamber 9| by a passageway 232 and having a valve opening 23I into gas delivery chamber 229. A second (or larger number) gas tube 232 receives gas from chamber 229 through a connection 233 operated thereby, which is particularly accurate because of the aforesaid adjustment for temperature, and which may be observed both for determining the elevation to which the plane has been flown and as a check on the delivery of gas for given elevations shown by the flow gauge.

For the purpose of providing this accurate altimeter a gauge 2I6 is formed with a face plate 2I6 of Figs. 1, 2 and 3, which gauge is supported upon a bracket 2I1, Figs. 1 and 2, having depending arms 2I8, 2I9, Figs. 2 and 8, screwed to the bracket plate I13. The gauge has thereon a gauge extension 220, and through an opening therein runs a rod 22I held at 222 by means 01' a spring 221' in continuous contact with the front wall 205 of the aneroid 20I. attached thereto within guage casing 223 a rack 224, Fig. 10, engageable with a pinion 225 on a shaft 226 upon which is mounted the gauge needle 221 and the coil spring 221.

Calibrations on the face 2I6' of gauge 2I6 are placed to indicate elevations or altitudes in thousands of feet and of course reflect the extent of outer movement of theend plate 205 of aneroid "I and in effect the degree of opening of the volume valve controlled by thevalve rod 2I3. Observation of the altimeter gauge 2I6 made in conjunction with observation of the flow valve H2 givesvisibly to the aviator or other occupant of an ascending plane the actual elevation at any time, and by comparison of that eleva- The rod 22I has identical with the connection 86. In this manner a plurality of individuals (in the example shown two) may be simultaneously served with automatically controlled added oxygen gas.

.The above recited instrumentalities provide means for automatically controlling flow of oxygen to one or more aviators or other occupants of an airplane at varying altitudes. Since, however, from various causes such automatic devices sometimes fail I have provided in conjunction with the flow valvewhich shows the volume of gas going to the wearer of the mask at designated elevations, a second and independent means comprising a hand valve and connections for controlling the flow of gas to the mask. This hand valve is the needle valve 53-,56 heretofore described. As shown in Fig. 2, gas passes through the valve passageway 52 and past the needle valve 53, adjustable by the hand screw 58, into a chamber 235 from which it passes from a connection 236, Fig. 2, to a delivery pipe 231, shown in full and dotted lines in Fig. 1.

Pipe 231, as clearly shown in Figs. 2 and 16, delivers to the passageway I00 through block 99 and tube IIJI to passageway I04 and thence through passageway I05, Fig. 3, to passageway I06 in flow valve tube I I2 and from there through pipes II1 and I2I to the mask I24.. Thus the gas controlled by the needle valve 53-56 passes.

through'the flow' valve to the pipe I I1 in the same manner as gas which is automatically regulated by the aneroid. and thermostatv heretofore described, and a perfect safety arrangement is provided for the use of mask wearers at high altitudes if and when the automatic control should fail.

As shown in Figs. 14 and 15 a modified support may be employed which is quite practical for somewhat larger gas tanks than can be conveniently assembled in the support of Fig. l. This support comprises side bars 239, 240 connected by transverse bars 24I, 242 and 243. Feet 244, preferably of rubber, are secured to the bars 239 and 240. Spanners 245 and 246 are positioned to permit the tank 241 to be inserted through them so as to rest upon transverse bars 24!, 242 and 243. 'Vertical posts 248 and 249 extend on either side of the tank 241 and are provided with threaded upper ends 250 and 25I and with shoulders 252 and 253 supporting compression springs 254 and 255. Upon the threaded elfds 250 and 25I of posts 248 and 249 is mounted a movable cross bar 256 which engages the springs 254 and 255 and also engages the center 01. tank 241. An ordinary nut 251 screwed on the post 250 holds one end of the cross bar 256 and a hand nut 259 similarly holds the other end of cross bar 256 on the end 25I of post 249. By screwing down on the hand nut 258 the tank 241 may be held firmly by cross bar 256. A bolt 259 extends between ends 260 and 26I of spanners 245 and 246 and supports a handle 262.

The tank 241 so far as its gas outlet valve arrangement is concerned is identically the same as the'tank 28 comprising a neck 36, a valve handle 38, and a connecting nut 4| and nipple M. In practice the nut and nipple of the construction of Fig. 1 will lie parallel with the bottom plate 2|] and thus be held normally horizontal while the nut and nipple 4l4| of Fig. 14 will be extended transversely to the plane of its support and therefore extend normally vertical. The parts shown in Figs. 14 and 15 are the same in operative arrangement as the parts of Figs. 1 to 13 and make their connection with the nipple 4| in the same way, so showing of the details of their manner of support is eliminated as unnecessary.

The advantages of my invention have appeared quite fully in connection with the detailed description thereof heretofore given. Some of these advantages, as is readily understood, reside in the fact that a complete oxygen delivery unit for aviation .purposes, including a tank of oxygen at suitable pressure, is assembled in a compact manner upon a single simple support which can be transferred from place to place and taken into any airplane, whether for military or commercial purposes, which it is desired to take into altitudes so high that the administration of oxygen becomes necessary.

Another advantage resides in the fact that the unit provides automatic aneroid and thermostatic control for varying flow of oxygen to meet conditions at varying elevations and pressure and at varying temperatures, and also manual means for controlling the flow of oxygen independently of the automatic means if and when that should fail. Further, the unit provides a system of gauges and a flow valve positioned and adapted to be positioned to be easily observed wherever the unit may be set relative to an aviator or occupant of the plane, which gauges will at all times inform the wearer of the mask, or the operator of the airplane, of the volume of oxygen which he is receiving whether from the automatic control means or the hand controlled means, and which will advise him of any failure or tendency of failure of the automatic control means so that he can meet the danger resulting from such failure by employing the hand controlled means. 4

Further, the invention provides a highly efiicient flow valve construction jointly operated for variations of air pressure (altitude) and temperature by an aneroid and a thermostat to produce exceptionally eifective and dependabl control of the flow of oxygen through automati variation of the extent of port opening to control the volume of flow as shown by the flow gauge, and as required by conditions of atmospheric pressures and temperatures.

A further very great advantage of my invention resides in the fact that the arrangement for accurately opening the flow valv more or less according to elevation and temperature by the joint operation of an aneroid and bimetallic thermostat member not only accomplishe correct increase and decrease of flow of oxygen for different elevations at different temperatures, but also, through the same movement of th valve operating means so effected, operates the needle of an altimeter to show with extraordinary accuracy the actual elevation of the plane at any time. This altimeter is thus operated with a high degree of accuracy for elevation through the aneroid with compensating bodily adjustment for temperature by the thermostat.

A further advantage of the invention resides in the fact that the aforesaid altimeter and flow gauge may be observed simultaneously. The altimeter shows correctly the elevation, and the flow gauge indicates what volum of gas should be delivered at that elevation and of course will show to the operator whether in fact delivery of oxygen gas is taking place at the rate called for for the actual elevation shown.

I claim;

1. In a portable oxygen aviation unit an oxygen tank and means for supporting it, a mask and means for conveying oxygen from the tank to the mask including an aneroid and a variable fiow' gauge, a valve adapted. to cooperate with said aneroid comprising two chambers separated by a web having a valve opening therethrough connecting the chambers, a valve rod carried through one of said chambers and said opening and having a circumferential diameter adapted to seal said opening gas-tight, said valve rod being progressively cut away from zero to a maximum depth along one sid thereof, so that expansion of the aneroid will move the rod through said opening and first produce a minimum flow opening which will then be progressively and uniformly increased as the aneroid expands from going into higher elevations and lower pressures.

2. In a portable oxygen aviation unit an oxygen tank and means for supporting it, a mask and means for conveying oxygen from the tank to the mask including an aneroid and a variable flow gauge adapted to cooperate with said aneroid, said valve comprising two chambers separated by a web having a valve opening therethrough connecting the chambers, a valve rod carried through one of said chambers and said opening and having a circumferential diameter adapted to seal said opening gas-tight. said valve rod being progressively cut away from zero to a maximum depth along part of one side thereof, so that expansion of the aneroid will move the rod through said opening and first produce a minimum flow opening which will then be progressively and uniformly increased as the aneroid expands because of going into higher elevations and lower pressures. v

3. In a portable oxygen aviation unit an oxygen tank and means for removably supporting it, a mask and means for conveying oxygen from the tank to the mask including a variable flow valve, an aneroid adapted to operate said valve, a thermostat rigidly mounted on said supporting means, means connecting the aneroid with said thermostat adapted to move the aneroid bodily, and a connection from said aneroid forming part of said variable flow valve whereby the aneroid and the thermostat in moving th same bodily jointly effect opening of the variable flow valve to a greater or less degree according to enveloping conditions of air pressure and temperature.

4. In a portable oxygen aviation unit an oxygen tank and means for removably supporting it, a mask and means for conveying oxygen from the tank to the mask including a variable flow valve, an aneroid adapted to operate said valve, a thermostat rigidly mounted on said supporting means, means connecting the aneroid with said thermostat adapted to move the aneroid bodily, a connection from said aneroid forming part of said variable flow valve whereby the aneroid and the thermostat in moving the same bodily jointly efiect opening of the variable flow, valve to a greater or less degree according to enveloping conditions of air pressure and temperature, a gauge calibrated to show elevations in thousands of feet including a gauge needle, and a connection from said aneroid whereby joint action of the aneroid and of the thermostat moving the aneroid bodily will operate the needle to provide a temperature compensated altimeter.

5. In an oxygen aviation unit an oxy en tank and means for removably supporting it, a mask and means including a regulating valve and a flow gauge for connecting the mask to the tank, said flow gauge carrying indications of volume of oxygen being delivered for indicated altitudes, means for automatically controlling the flowioi oxygen from the regulating valve throughthe flow gauge to a mask at varying'altitudes and temperatures, and an altimeter operated by said automatic controlling means for indicating elevations, whereby the operator by inspection of the altimeter and flow gauge will be informed as to whether the correct volumes of oxygen are being delivered for the altitude indicated on the altimeter.

6. In a portable oxygen aviation unit a casing forming a support adapted to be transported by hand into or out of an airplane, a tank of oxygen removably mounted in the casing, means in the casing including a system or conduits and a mask for conveying and delivering oxygen to an aviator, a variable flow valve in the casing for controlling the rate or now or volume 01 gas going to the mask, an aneroid having an operator member for automatically operating the flow valve in response to changes of external pressures at difierent elevations, a thermostat mounted on the aneroid and adapted to move it and the operator member on the aneroid member bodily when changesoi temperature occur to compensate for variations of gas expansion in, the aneroid due to such changes of temperature, and an altimeter with connection therefrom to the aneroid whereby the Joint action of aneroid and thermostat moving it bodily will cause the altimeter to show correct temperature-compensated altitudes.

Jay A. HEIDBRIN'K. 

